/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.metadata.idtable.entry;

import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.commons.utils.TestOnly;
import org.apache.iotdb.db.conf.IoTDBDescriptor;

import java.util.function.Function;

/**
 * factory to build device id according to configured algorithm
 */
public class DeviceIDFactory {
    Function<String, IDeviceID> getDeviceIDFunction;

    // region DeviceIDFactory Singleton
    private static class DeviceIDFactoryHolder {

        private DeviceIDFactoryHolder() {
            // allowed to do nothing
        }

        private static final DeviceIDFactory INSTANCE = new DeviceIDFactory();
    }

    /**
     * get instance
     *
     * @return instance of the factory
     */
    public static DeviceIDFactory getInstance() {
        return DeviceIDFactoryHolder.INSTANCE;
    }

    private DeviceIDFactory() {
        if (IoTDBDescriptor.getInstance().getConfig().isEnableIDTable()
                && IoTDBDescriptor.getInstance()
                .getConfig()
                .getDeviceIDTransformationMethod()
                .equals("SHA256")) {
            getDeviceIDFunction = SHA256DeviceID::new;
        } else {
            getDeviceIDFunction = PlainDeviceID::new;
        }
    }
    // endregion

    /**
     * get device id by full path
     *
     * @param devicePath device path of the timeseries
     * @return device id of the timeseries
     */
    public IDeviceID getDeviceID(PartialPath devicePath) {
        return getDeviceIDFunction.apply(devicePath.toString());
    }

    /**
     * get device id by full path
     *
     * @param devicePath device path of the timeseries
     * @return device id of the timeseries
     */
    public IDeviceID getDeviceID(String devicePath) {
        return getDeviceIDFunction.apply(devicePath);
    }

    /**
     * reset id method
     */
    @TestOnly
    public void reset() {
        if (IoTDBDescriptor.getInstance().getConfig().isEnableIDTable()
                && IoTDBDescriptor.getInstance()
                .getConfig()
                .getDeviceIDTransformationMethod()
                .equals("SHA256")) {
            getDeviceIDFunction = SHA256DeviceID::new;
        } else {
            getDeviceIDFunction = PlainDeviceID::new;
        }
    }
}
